This invention deals with the art of coolers especially for cooling high power semi-conductors.
A variety of types of heat sink members are known for cooling semi-conductor power elements. However, because of the practical problems involved, conventional commercial techniques often involve the use of a relatively thick and hence inefficient hollow heat sink member. The semi-conductor devices may be stacked between such members, and the heat sink normally connected by dielectric tubing to the coolant source. The heat sink members often have machined complex or convoluted passageways therein which involve increased cost and complex material preparation procedures.
Other problems exist in conventional practice. For example, the coolant flow passages in the heat sink member are desirably made as narrow as possible to make the member as thin as possible. Coolant must be circulated through the heat sink at a high rate of flow and the components must be able to withstand a high pressure without leaking.
Also, known coolers may be designed with straight liquid conducting channels, mainly because of their simple manufacturing technology. Such coolers are usually formed of material having a good heat conductivity, such as copper. However, laminar layers are formed on the walls of such straight channels, thereby reducing the heat transfer from the body of the cooler of the cooling medium. There are also known arrangements wherein a circular plate with radial grooves is fitted on at least one side thereof to a flat connecting piece provided with concentric grooves for the supply of cooling liquid. These arrangements are simple from a technical standpoint; however, because of insufficient turbulence of the cooling liquid during its passage through the cooler, they do not provide the required cooling effect.
Fabricated, multi-piece coolers having machined passages are known; however, the machining operation is quite expensive and also requires extensive soldering or bonding operations making them prone to leaks. Casting operations are less expensive and are quite desirable, but have shown heat exchange defects.